Automatic pressure release valve

ABSTRACT

A fully automatic bottle and can crusher in which articles are fed, one at a time, into the crusher by a feeder. The feeder control is responsive to the presence of an article in the feeder, and the crusher control is responsive to the presence of an article in the crusher. The crusher is operated by an electrically actuated hydraulic release valve which discontinues operation of the crusher at a predetermined hydraulic pressure. The valve has a hydraulically actuated means for moving a spool to a pressure release position in response to the predetermined pressure.

United States Patent Inventor Stanley E. Keaglc Minneapolis, Minn.

Appl. No 846,883

Filed Aug. 1, 1969 Division of Ser. No. 668,431, Sept. 18. 1967, Pat.No. 3,517,607

Patented July 13, 1971 Assignee Earl] Manufacturing Company Minneapolis,Minn.

AUTOMATIC PRESSURE RELEASE VALVE 17 Claims, 17 Drawing Figs.

U.S.Cl 137/115, 91/47,91/3l8,9l/356, 137/467 1111.01 ..G05dl1/00,Fl5b13/02 FieldolSeareh 91 47, 318, 356; 137 1 15,467

[56] References Cited UNITED STATES PATENTS 2,298,457 10/1942 Berges91/318 3,232,172 2/1966 Ziegelmeyer v. 91/318 X Primary ExaminerLavemeD. Geiger Assistant Examiner-David J. Zobkiw Attorney-Burd, Braddock &Bartz ABSTRACT: A fully automatic bottle and can crusher in whicharticles are fed, one at a time, into the crusher by a feeder. Thefeeder control is responsive to the presence of an article in thefeeder, and the crusher control is responsive to the presence of anarticle in the crusher. The crusher is operated by an electricallyactuated hydraulic release valve which discontinues operation of thecrusher at a predetermined hydraulic pressure. The valve has ahydraulically actuated means for moving a spool to a pressure releaseposition in response to the predetermined pressure.

AUTOMATIC PRESSURE RELEASE VALVE CROSS-REFERENCE TO RELATED APPLICATIONThis application is a division of U.S. application Ser. No. 668,431filed Sept. 18, 1967 now issued as U.S. Pat. No. 3,517,607.

SUMMARY OF INVENTION The invention relates to a pressure controlmechanism responsive to a predetermined fluid pressure in a system torelease the pressure in the system. The control mechanism is a valvehaving a body with a first cavity, a second cavity, and a fluid pathconnecting the first cavity with the second cavity. An inlet port opensto the path. A drain port opens to the first cavity. A valving memberlocated in the first cavity moves to a first position to block fluidflow through the first cavity from the path to the drain port and movesto a second position to permit fluid flow through the first cavitythereby reducing the pressure in the path. A pressure-responsive valvingmeans in the path operates in conjunction with a hydraulically actuatedmeans located in the second cavity to move the valving member to itssecond position when a predetermined fluid pressure is attained in thepath.

An object of the invention is to provide a self-contained automaticcontrol valve operable in response to a predetermined pressure torelease the pressure in a fluid system. Another object of the inventionis to provide a pressure release valve wherein a predetermined releasepressure can be adjusted. A further object of the invention is toprovide a pressure release valve which is externally actuated andautomatically returns to its initial operating position after apredetermined pressure is reached in the valve.

IN THE DRAWINGS FIG. 1 is a side view, partially cut away, of thecrushing apparatus of the invention;

FIG. 1A is a side view of a portion of FIG. 1 during operation of thecrusher;

FIG. 2 is a cross-sectional side view of one form of hydraulic controlvalve for use in the apparatus, the valve being in a pressure position;

FIG. 3 is a cross-sectional view of the valve of FIG. 2 in a drainposition;

FIG. 4 is a cross-sectional side view of the valve of FIG. 2 in astandby position;

FIG. 5 is a bottom view of the valve of FIGS. 2-4;

FIGS. 6-10 are cross-sectional views of the valve of FIG. 3 taken alongthe respectively numbered lines;

FIG. 11 is a cross-sectional view of a modified valve for use in theapparatus, the valve being in a pressure position;

FIG. 12 is a cross-sectional side view of the valve of FIG. 11 in adrain position;

FIG. 13 is a bottom view of the valve of FIG. 11; and

FIGS. 1416 are cross-sectional views of the valve body of FIGS. 11 and12 taken along the respectively numbered lines with the spool and otherinternal parts removed.

DESCRIPTION OF THE PREFERRED EMBODIMENT Crusher Structure The crushingapparatus is shown in FIG. 1. The articlecrushing means is here shown asa hydraulic crusher, generally designated 15, containing a bottle 16 tobe crushed. Feeding means, generally designated 17, is positionedadjacent crusher 1S, and is adapted to feed articles to be crushed intocrusher one at a time. A can 18 is disposed in a flexible chute 19leading to feeding means 17 so that the lower edge of can 18 abuts aportion of feeding means 17. Chute 19 extends upwardly to a mouth, notshown, which may be mounted in the back portion of a bar or other placefrom which cans and bottles must be sent for disposal. Cans and bottlesto be disposed of are dropped into the mouth of chute 19 and slidedownward to the position of can 18. The crushing apparatus also includesa refuse container 20 which collects the broken and crushed pieces ofbottles and cans. Container 20 is removable from the crushing apparatusfor disposal of the crushed material.

Feeding means 17 includes an elevator platform 21 containing anelongated aperture 22 therethrough and downwardly extending endportions, one of which includes a vertical slot 56. Platform 21 isconnected to a support post 23 which cooperates with a solenoid elevatoroperator 24. Support 23 includes a pair of hemispherical depressions 25and 26 which cooperate with an adjusting screw 27, a bias spring 28 anda ball 29 to form a detent mechanism for retaining platform 21 in eithera raised or lowered position.

The control means for feeding means 17 includes switching means, hereshown as a'microswitch 30 of standard construction, having a switchoperator arm 31 extending upwardly and terminating in a roller 32positioned so that it extends through aperture 22 when platform 21 is ina lower position 33, which is shown in dotted lines. Switch 30 isconnected to a source 'of power, not shown, and further connected incontrolling relationship to solenoid 24. Depression of switch arm 31closes a circuit which energizes solenoid 24 thereby raising platform 21from lower position 33 to the upper position shown in FIG. 1 (solidlines).

Crusher 15 includes a lower stationary platen 39 which is rigidlyconnected to an upper stationary platen 40. Disposed between platens 39and 40 is a movable platen 41. A hydraulic cylinder 42 is rigidlymounted to lower platen 39 and contains a hydraulic ram 43 which has itsupper end attached to the underside of movable platen 41. Movable platen41 is driven upward toward upper stationary platen 40 by hydrauliccylinder 43 during the crushing operation. Platen 41 is returned to itsoriginal position after the crushing operation by reset means, hereshown as a return spring 44. A plurality of guide bolts 45 connect upperplaten 40 to lower platen 39 in a predetermined, fixed, spaced relation.Movable platen 41 contains a plurality of guide holes through whichguide bolts 45 are disposed to form guide means therefor as it moves upand down in the crushing operation. A stop member 46 is provided so thatmovable platen 41 returns to the same lower position after each crushingoperation.

The control means for crusher 15 includes a switch 47, which mayconveniently be a conventional microswitch, having an actuating arm 48extending downwardly therefrom so that the lower end of arm 48 isdisposed in the space between upper platen 40 and movable platen 41 whenmovable platen 41 is in the lower position. Electrically conductiveleads 49 extend from switch 47 to a source of power, not shown, and to asolenoid 66 which controls a hydraulic valve, generally designated 65,so that actuation of switch 47 controls operation of solenoid 66.

Also included in the crushing apparatus is means for resetting feedingmeans 17 to position 33 while movable platen 41 is being reset to itslower position. This reset mechanism for feeding means 17 includes alatch bracket 50 which extends downwardly from movable platen 41.Rotatably attached to latch bracket 50 is a latch member 51. Attached toone end of latch member 51 is a latch bias spring 52 whose other end isattached to the lower side of movable platen 41. When movable platen 41is in the position shown in FIG. 1, latch member 51 bears against alatch stop 53 which extends upwardly from stationary platen 39. A latchcatch bracket 54 is rigidly attached to the depending end of elevatorplatform 21 adjacent crusher 15. Rotatably disposed in catch bracket 54is a latch catch 55, and immediately above latch catch 55 is the groove56 in the end of elevator platform 21.

. The hydraulic system of the crushing apparatus includes a hydraulicpump 60 which is mounted on top of a hydraulic fluid reservoir 61. Pump60 is driven electrically from a source of power, not shown, and isturned on and off from a master switch, also not shown, which alsocontrols the power to switches 30 and 47 and to solenoids 24 and 66.Reservoir 61 contains a hydraulic fluid filter 62 which is connected topump 60 by a pump intake line 63. From pump 60, a pressure supply line64 extends upwardly to the hydraulic control valve 56, which is actuatedby solenoid 66. A pair of leads 67 from solenoid 66 are connected to thesource of power and to one of leads 49 of switch 47 by conductors, notshown. From valve 65, a ram supply and return line 68 extends to thebottom of cylinder 42. A pair of drain lines 69 and 71 extend downwardlyfrom valve 65, joining into one line which empties into reservoir 61.The entire apparatus including crusher 15, feeding means 17, and thehydraulic system is mounted in a support structure 70, which supportsthe various portions and encloses the apparatus to prevent broken piecesof glass or other material'from escaping from the crushing area.

OPERATION OF CRUSHING APPARATUS Assume that the entire apparatus isempty of materials to be crushed. Elevator platform 21 will be in.dotted position 33 and movable platen 41 will be in the lower position,as shown in FIG. 1. The first piece to be crushed is fed into the mouthof tube 19 and slides downward in tube 19 and across the top of elevatorplatform 21 (which is flush withthe lower surface of tube 18) until itstrikes the edge of movable platen 41 which is closest to elevatorplatform 21. The article is stopped by this leading edge of movableplaten 41 and any articles behind it will be stopped by the upper end ofthe article to be crushed and the depending end of platform 21 as itrises. As the article slides over the upper surface of elevator platform21, it strikes roller' 32 depressing arm 31 actuating switch 30.Actuation of switch 30 causes power to be supplied to solenoid 24 whichthen moves elevator platform 21 to the upper position as shown inFIG. 1. In the detenting mechanism, ball 29 is forced into depressionthereby retaining platform 21 in the upper position even though pressurehas been removed from roller 32 so that it returns to its normalposition opening switch and removing power from solenoid 24.

While elevator platform 21 is in its upper position, the depending edgeof platform 21 adjacent tube 19 forms an abut ment member which preventsfurther articles, such as can 18, from entering the feeding means whilethe previous article is being crushed.

When elevator platform 21 reaches its upper position, its upper surfaceis flush with the upper surface of movable platen 41 and the article tobe crushed, such as bottle 16, slides downward onto platen 41. As thearticle reaches the opposite end of crusher 15, it engages arm 48 movingit and actuating switch 47. Switch 47, in turn, actuates solenoid 66which actuates hydraulic valve 56 to a position wherein hydraulic fluidunder pressure can be supplied through ram supply line 68 to hydrauliccylinder 42.

Hydraulic fluid is drawn from reservoir 61 through filter 62 and pumpsupply line 63 to hydraulic pump 60. Hydraulic fluid under pressure issupplied from pump 60 through pressure line 64 to valve 65 and throughvalve 65 to ram supply line 68. The hydraulic fluid causes ram 43 to beforced upward out of cylinder 42 thereby raising movable platen 41upwardly along guide bolts 45 toward upper stationary platen 40. Thisupward motion of platen 41 crushes the article until a predeterminedhydraulic pressure is reached in cylinder 42 and valve 65. At that time,valve 65 is actuated to a position which removes supply pressure fromthe hydraulic fluid in the cylinder 42 and provides a return channelthrough line 68 and valve 65 to drain line 69. Once the hydraulicpressure is removed'from ram 43, return spring 44 draws movable platen41 back down to the lower position abutting stop 46, thereby forcing thehydraulic fluid back through line 68, valve 65 and drain line 69 toreservoir 61.

The latching mechanism provides a means for resetting elevator platform21 to its lower position upon the return of movable platen 41 to itslower position. While movable platen 41 is in its lower position, latchmember 51 is in a position with its leading edge retracted sufficientlyto permit latch catch 55 to move upwardly past member 51 withoutengaging it. Latch catch 55 travels upwardly with elevator platform 21as its rises to the solid position.

Catch member 55 is attached to bracket 54 in such a manner that it isrotatable from the position shown in FIG. 1 to a position in which thepointed edge of catch member 55 is vertically upward, but catch 55 iseither biased or constructed so that as soon as the pressure rotating itupwardly is removed, catch 55 drops back to the position shown in H6. 1where it stops. Thus, catch member 55 is rotatable through an angle ofapproximately 90 degrees and, in the absence of pressure from below, isin the position shown in FIG. 1.

As platen 41 moves upwardly, latch member 51 lifts off of stop member53. Bias spring 52 then contracts rotating latch member 51 in acounterclockwise direction so that its upper leading edge extendsoutwardly toward latch catch 55. With continued upward movement, latchmember 51 engages catch member 55 from the lower side and rotates member55 upwardly until latch member 51 slides past catch member 55. Catchmember 55 drops back to its original position, and latch member 51continues to move upwardly with platen 41 passing through groove 56inthe depending end of elevator platform 21 as is shown in FIG. 1A.

When movable platen 41 returns to its lower position, the outwardlyextending end of latch member 51 temporarily engages the upper surfaceof catch member 55. The spring tension on bias spring 52 is great enoughto maintain pressure on catch 55 and elevator platform 21 until ball 29disengages from depression 25, whereupon elevator platform 21 drops backto its lower position 33 so that it is reset to feed in the next articleto be crushed. As movable platen 41 approaches the bottom of its travel,latch member 51 again engages stop member 53 and is rotated in aclockwise direction to the position with the leading edge out of theline of travel of catch member 55.

Valve Structure FlGS. 2-10 Hydraulic valve 65, which controls theoperation of crusher 15, also includes a novel structure which is shownin FIGS. 2 through 10. A valve body 74 contains a pressure inlet port75, a ram supply and return port 76, a ram drain port 77 and a pressuredrain port 78, which are best shown in FIG. 5. The remainder of thevalve structure can best be seen by referring to FIGS. 2-4 and 6-10.Valve body 74 also includes a first cavity 79 in which a spool 80 isdisposed. Body 74 also contains a second cavity 81 and a passageway 82which connects ports 75 and 76. A first interior port 83 connects oneend of passageway 82 adjacent ram supply and return port 76 to spoolcavity 79. A second interior port 84 connects a portion of passageway 82adjacent pressure port 75 to spool cavity 79.

A first restricted passage 85 connects the opposite end of passage 82 toa valve chamber 86 within valve body 74, and a second restricted passage87 connects valve chamber 86 with second cavity 81. The right end ofpassageway 82, restricted passage 85, valve chamber 86 and secondrestricted passage 87 provide a first fluid-conducting path betweenpressure inlet port 75 and second cavity 81. A restricted drainpassageway 88 connects the right end of second cavity 81 with pressuredrain port 78. Restricted passageway 88 provides a secondfluid-conducting path in valve body 74. Further interior drain ports 89and 90 connect portions of spool cavity 79 to a passage 91 and ram drainport 77 and to a passage 92 and supply drain port 78, respectively.Valve body 74 contains a venthole 93 connecting one end of second cavity81 with the outside atmosphere for equalizing pressure. Finally, apassageway 102 connects the adjacent ends of second cavity 81 and spoolcavity 79.

A hydraulic spool-actuating means is provided in second cavity 81 by apiston 94 which is connected to an actuating rod 95. The end ofactuating rod 95 remote from piston 94 extends through passageway 102.Disposed about piston 94 is an O-ring seal 96 to prevent hydraulic fluidfrom flowing into the portion of cavity 81 communicating with venthole93. A bias mechanism, here shown as bias spring 97, is disposed betweenpiston 94 and the wall of cavity 81 adjacent cavity 79. Spring Valve 65also includes a hydraulic fluid pressure responsive mechanism whichincludes a valve closure member 98 disposed in valve chamber 86. Closuremember 98 cooperates with a valve seat 99 formed in valve body 74adjacent restricted passage 85. An adjustable bias means, here shown asa bias spring 100 and an adjusting screw are provided to vary thepressure with which closure member 98 is forced against seat 99.

Spool 80 has a first land 105, a second land 106 and a third land 107separated from one another by shank portions 108 and 109, respectively.Spool 80 further includes an exterior shank portion 110 and connectingmeans 111 which operatively connect shank portion 110 and spool 80 tosolenoid 66. Disposed about lands 105, 106 and 107 are O-rings 96 whichprevent hydraulic fluid from leaking between ports or out of valve 65.

The hydraulic line connections to valve 65 are as follows: pressure port75 is connected to the pressure supply line 64, ram supply and returnport 76 is connected to ram supply and return line 68, ram drain port 77is connected to drain line 69 and pressure drain port 78 is connected todrain line 71.

Valve Operation FIGS. 2-10 When an article to be crushed enters crusherand actuates switch 47, solenoid 66 moves spool 80 to the pressureposition shown in FIG. 2. In this position, fluid under pressureentering through port 75 flows in passageway 82 to port 76, to interiorports 83 and 84, and to restricted passage 85. The pressure generated onspool 80 at ports 83 and 84 freezes spool 80 in that position eventhough energy is removed from solenoid 66. Hydraulic fluid flowing outof port 76 actuates hydraulic ram 43. At the same time, hydraulicpressure builds up in restricted passage 85 on closure member 98 whichis preset to open at a specific hydraulic pressure, e.g. 500 p.s.i.Until that hydraulic pressure is reached, valve member 98 is firmlyseated on seat 99 and no fluid flows through valve chamber 86.

As soon as the hydraulic pressure on closure member 98 reaches thepredetermined value, closure member 98 cracks away from seat 99 andhydraulic fluid flows through chamber 86 and restricted passage 87 tothe end of second cavity 81 remote from cavity 79. The pressure of fluidin cavity 81 forces piston 94 toward cavity 79 against the bias ofspring 97. As piston 94 moves toward cavity 79, air is expelled from theportion of cavity 81 adjacent cavity 79 through vent hole 93. Actuatingrod 95 moves through passage 103 and bears against the adjacent end ofspool 80.

Motion of piston 94 toward cavity 79 causes spool 80 to be moved to thedrain position shown in FIG. 3. Restricted passages 87 and 88 aredesigned so that fluid pressure build up in cavity 81 as long as closuremember 98 is off of seat 99. As soon as spool 80 moves to the positionshown in FIG. 3, hydraulic supply pressure is removed from hydraulic ram43 because interior port 84 communicates with interior port 90 throughthe portion of cavity 79 about shank portion 108 thereby allowing fluidunder supply pressure to flow to drain port 78 without substantialresistance. At the same time, interior port 83 communicates withinterior port 89 through the portion of cavity 79 about shank portion109 thereby allowing fluid from cylinder 42 to flow to drain port 77without sub stantial resistance. These interior communications providetwo separate drain circuits for hydraulic fluid.

When valve 65 is in the drain position, pressure is removed from ram 43,return spring 44 and ram 43 exerts sufficient pressure on the fluid incylinder 42 to force it back through pipe 68 and port 76 into valve 65.The hydraulic fluid flowing from port 76 continues upward through port83, cavity 79, port 89, passages 91, drain port 77 and drain line 69 toreservoir 61. Fluid from pump 60 enters port 75 and flows through port84, cavity 79, port 90, passageway 92, port 78 and drain line 71 toreservoir 61. As soon as valve 65 is in the drain position. fluidpressure valve member 98 drops and member 98 97 yieldably biases piston94 toward the opposite end of cavity immediately reseats itself on seat99. Fluid pressure in cavity 81 also drops, and bias spring 97 forcespiston 94 away from cavity 79 expelling the fluid from cavity 81 throughrestricted passage 88 and drain port 78.

Fluid is expelled from cavity 81 until piston 94 reaches the end of itstravel as shown in FIG. 4 leaving valve 65 in the standby position. Inthat position, valve 65 is ready to receive another actuating signalfrom solenoid 66 which will move spool to the pressure position shown inFIG. 2 again.

It can be seen that modifications can be made to the apparatus withoutdeparting from the contemplated scope of the invention. For example,normally open and normally closed switches and valves can be replaced bytheir reverse counterparts with suitable circuitry and bias reversals.Also, a suitable valving arrangement can be substituted for the simplerestricted passage 88 to control expulsion of fluid from cavity 81 whenfluid under pressure is removed therefrom. Other modifications will beapparent to those skilled in the art.

Valve Structure and Operation -FIGS. 11-16 A modified hydraulic valve isshown in FIGS. 11 through 16. This valve can be substituted for thatshown in FIGS. 2 through 10 in the apparatus of the invention and is thepresently preferred structure. The valve of FIGS. 11 through 16 isconstructed and operates in a manner similar to that of the valve ofFIGS. 2 through 10 with certain exceptions which are pointed outhereafter. Parts of the valve of FIGS. 11 through 16 which correspond tothose of the valve of FIGS. 2 through 10 are numbered with correspondingnumbers greater than the numbers on the valve of FIGS. 2 through 10.

An L-shaped passage 220 connects one end of valve chamber 186 to secondcavity 181 and to a metered orifice 221 which communicates withrestricted drain passageway 188. L-shaped passageway 220 and meteredorifice 221 provide the fluid path between chamber 186, cavity 181, andpassageway 188.

The means for actuating spool to its second position is a double-actingpiston arrangement which provides snap actuation. Plston 194, whichresponds to the fluid pressure transmitted into second cavity 181, actson a second piston 222 through a bias spring 223. Second piston 222 isattached to actuating rod and is biased to the right, as shown in FIG.11, by bias spring 197. Second piston 222 is held in the position shownin FIG. 11 by a detent mechanism, here shown as a hemisphericaldepression 224 in the wall of piston 222 into which a ball 225 is forcedby a bias spring 226. The detent mechanism retains piston 222 in theposition shown in FIG. 11 until piston 194 is driven to the left byfluid pressure to release the detent mechanism either by pressure ofspring 223 or by actual contact between pistons 222 and 194. Thepressure of spring 223 then forces piston 222 to the left rapidly andforcefully until it reaches the position shown in FIG. 12. This rapidforceful action causes positive snap actuation of spool 180 to the drainposition shown in FIG. 12. The snap action of the valve of FIGS. 11through 16 eliminates difficulties which are sometimes encounteredbecause of the pressure seal holding spool 180 in its first position. Afurther structural modification necessitated by the double-acting pistonis an additional venthole 193a communicating with the portion of secondcavity 181 to the left of second piston 22.

A second drain passageway is provided to assist in draining fluid fromhydraulic ram 43 when the valve is in the drain position. A secondinterior drain port 19011 is connected to a second ram drain port 1770by an interior passage 191a. Ram drain port 1770 is connected to fluidreservoir 61 by a second drain line, now shown, Addition of the seconddrain port requires an additional shank portion 229 and land surfaces227 and 228 on spool 180. In all respects, other than those describedabove, the valve of FIGS. 11 through 16 is constructed and operates inthe same manner as the valve of FIGS. 2 through 10.

The embodiments of the invention in which I claim exclusive property orprivilege are defined as follows:

l. A valve comprising: a valve body having a plurality of portsincluding a load port; an inlet port communicating with a first interiorcavity, the body further having a second cavity and a first fluidconducting path connecting the inlet port and the load port, and theinlet port and the second cavity; a first drain port communicating withthe first cavity; a spool disposed in the first cavity and movablebetween first and second positions therein; pressure-responsive valvingmeans disposed in the first path between the inlet port and the secondcavity and biased in a first position until a predetermined fluidpressure within the path is exceeded, the valving means being movable toa second position by the fluid pressure when the predetermined pressureis exceeded thereby causing a change in fluid pressure in the secondcavity; first spool-actuating means for moving the spool to its firstposition wherein communication between the first drain port and thefirst cavity is closed and fluid under pressure can flow through thevalve from the inlet port in such a manner that fluid pressure increasesat the pressure-responsive valving means; and second spool-actuatingmeans for moving the spool to its second position wherein fluid underpressure can flow through the valve without significant fluid pressureincrease in the first path, the second spool-actuating means beingdisposed in the second cavity, maintained in a first position while thepressure responsive valving means is in its first position, and movableto a second position in response to a fluid pressure change in thesecond cavity resulting from movement of the pressureresponsive valvingmeans to its second position, the second actuating means beingpositioned so that it moves the spool to its second position uponmovement of the second actuating means to its second position.

2. A valve according to claim 1 wherein: the plurality of ports includesa second drain port; and which further com prises fluid pressure reliefmeans connecting the second cavity to the second drain port forrelieving fluid pressure in the second cavity when thepressure-responsive valving means is in its first position.

3. A valve according to claim 1 wherein: the plurality of ports furtherincludes a second drain port; the first path has a predetermined minimumdiameter and communicates with a first portion of the second cavity,adjacent one end thereof; the pressure-responsive valving meansincluding a valve seat formed by a portion of the wall of the firstpath, a valve closure member which, in the first position, cooperateswith the seat to from a fluidtight seal, and which, in the secondposition has moved away from the seat thereby allowing fluid pressure inexcess of the predetermined pressure to be transmitted to the secondcavity, and adjustable biasing means cooperable with the closure memberto yieldably bias the closure member in the first position; the valvebody further includes a passageway directly connecting one end of thefirst cavity to the opposite end of the second cavity and a secondfluid-conducting path connecting the first portion of the second drainport, the second path having a maximum diameter less than the minimumdiameter of the first path; and the second spoolactuating meansincluding piston means slidably positioned in the second cavity influidtight engagement with the walls thereof between the first portionand the opposite end, including a member operably connected to thepiston means, slidably disposed in the passageway, and adapted tocooperate with the spool to move it to its second position when fluidpressure in excess of the predetermined pressure is transmitted to thefirst portion of the second cavity thereby moving the piston meanstoward the opposite end; and which further comprises yieldable biasmeans disposed in the second cavity between the piston means and theopposite end for moving the piston means away from the opposite end uponreturn of the closure member to the first position.

4. A valve according to claim 3 wherein: the spool includes an extensionprojecting through and outwardly from the valve body; and the firstspool-actuating means includes a solenoid mounted coaxially with theextension and cooperable therewith to move the spool to its firstposition upon application of electrical energy to the solenoid, thesolenoid being adapted for connection to a source of electrical energy.

5. The valve according to claim 1 including: means to bias thepressure-responsive means to its first position, and adjustable meansfor selectively varying the biasing force on the predetermined pressurecan be adjusted.

6. The valve according to claim 1 including: holding means to releasablylocate the second spool actuating means in its first position until asubstantial increase in pressure in the second cavity overcomes theholding means to move the further second spool-actuating means to itssecond position.

7. The valve according to claim 6 wherein: the holding means comprises ayieldable detent acting on the second spool actuating means.

8. A valve comprising: a valve body having a plurality of portsincluding an inlet port, a load port at least one drain portcommunicating with a first interior cavity, the body further having asecond cavity, a first fluid-conducting path connecting the inlet portand the load port, and the inlet port and the second cavity, the loadport and inlet port communicating with said one drain port only throughthe first cavity, the inlet port being connectable to a hydraulic fluidsupply, the load port being connectable to a hydraulic ram, and said onedrain port being connectable to a fluid reservoir; a spool disposed inthe first cavity and movable between first and second positions therein,said spool being constructed to block communication between the inletand load ports and said one drain port in the first position and toallow communication therebetween in the second position;pressure-responsive valving means disposed in the first path between theinlet port and the second cavity and biased in a first position until apredetermined fluid pressure within the first path is exceeded, thevalving means being movable to a second position by the fluid pressurewhen the predetermined pressure is exceeded thereby causing a change influid pressure in the second cavity; connecting means operativelyconnecting the spool to a solenoid so that actuation of the solenoidmoves the spool to its first position wherein when thepressure-responsive valving means is in its first position fluid underpressure can flow through the valve from the inlet port to only the loadport whereupon fluid pressure increases at the pressure-responsivevalving mean; and

hydraulically actuated means for moving the spool to its second positionwherein fluid under pressure can flow from the inlet port and the loadport to at least said one drain port with out significant fluid pressureincreases in said first path, the hydraulically actuated means beingdisposed in the second cavity, maintained in a first position while thepressureresponsive valving means is in its first position, and movableto a second position in response to a fluid pressure change in thesecond cavity resulting from movement of the pressureresponsive valvingmeans to its second position, the hydraulically actuated means beingpositioned so hat it moves the spool to its second position uponmovement of the hydraulically actuated means to its second position.

9. The valve according to claim 8 including: holding means to releasablylocate the hydraulically actuated means in its first position until asubstantial increase in pressure in the second cavity overcomes theholding means to move the hydraulically actuated means to its secondposition.

10. The valve according to claim 9 wherein: the holding means comprisesa yieldable detent acting on the hydraulically actuated means. v

11. A valve comprising: a valve body having a first interior cavity, asecond interior cavity, a fluid-conducting path open to the first cavityand the second cavity, and an inlet port and a load port communicatingwith the path, a drain port communicating with the first cavity, amovable valving member disposed in the first cavity movable in a firstposition to block the flow of fluid from the path to the drain port andmovable to a second position to permit the flow of fluid from the pathto the drain port, pressure-responsive valving means disposed in thepath between the inlet port and the second cavity, saidpressure-responsive valving means being maintained in a first positionuntil a predetermined fluid pressure within the path is exceeded, thevalving means being movable to a second position by the fluid pressurewhen the predetermined pressure is exceeded thereby causing an increasein fluid pressure in the second cavity, first actuating means for movingthe valving member to its first position, second actuating means formoving the valving member to its second position wherein the fluid underpressure in the path can flow through the valve without significantfluid pressure increases in the path, said second actuating means beingdisposed in the second cavity and movable to a second position inresponse to a substantial increase in the fluid pressure in the secondcavity resulting from movement of the pressure-responsive valving meansto its second position.

12. The valve according to claim 11 including: means to bias thepressure-responsive valving means to its first position, and adjustablemeans for selectively varying the biasing force on thepressure-responsive valving means whereby the predetermined pressure inthe path can be adjusted. C

13. The valve according to claim 11 including: holding means toreleasably locate the second actuating means in its first position untila substantial increase in pressure in the second cavity overcomes theholding means to move the ac tuating means to its second position.

14. The valve according to claim 13 wherein: the holding meanscomprising a yieldable detent acting on the actuating means.

15. The valve according to claim 11 wherein said first actuating meansincludes: an external control member for moving the valving member toits first position.

16. The valve of claim 1] including: fluid pressure relief meansconnecting the second cavity to a second drain port for relieving fluidpressure in the second cavity when the fluid pressure responsive valvingmeans is in its first position.

17. The valve according to claim 11 including: adjustable means forselectively varying the biasing force on the pressure responsive valvingmeans whereby the predetermined pressure in the path can be adjusted.

P0-1050 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,592,217 Dated 1971 Inventor(s) Stanley H. Keagle It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 3, line 2, "56" should he 65.

line 29, after "31" andis omitted.

line 49 "56" should he -65" Column 4, line 1, "its" should be it-.

Column 5, line 48, "103" should he l(l2- line 52, "build" should hehuilds. line 71, "passages" should he passage-.

Column 6, line 17, after "fluid", "under" should he omitted.

line 62 "22" should he -222- line 68, "now" should he --not-.

Column 7, line 46, "from" should be form.

line 55, after "the" -second cavity to the is omitted.

Column 8, line 5, after "on" the pressure responsive means whereby theis omitted. line 11, "further" should be omitted. line 17, after "loadport" and is omitted.

line 42, "mean" should he means. line 45, after "port to", "at least"should be omitted. line 53, "hat" should he -that.

Column 9, line 19, after "adjusted." "C" should he omitted.

Signed and sealed this L th day of January 1 972.

emmy. 3

Attest:

EDWARD MJMJTGHEfQJl-l. ROBERT GOTTSGHALK Atte sting Officer ActingCommissioner of Patents

1. A valve comprising: a valve body having a plurality of portsincluding a load port; an inlet port communicating with a first interiorcavity, the body further having a second cavity and a first fluidconducting path connecting the inlet port and the load port, and theinlet port and the second cavity; a first drain port communicating withthe first cavity; a spool disposed in the first cavity and movablebetween first and second positions therein; pressure-responsive valvingmeans disposed in the first path between the inlet port and the secondcavity and biased in a first position until a predetermined fluidpressure within the path is exceeded, the valving means being movable toa second position by the fluid pressure when the predetermined pressureis exceeded thereby causing a change in fluid pressure in the secondcavity; first spool-actuating means for moving the spool to its firstposition wherein communication between the first drain port and thefirst cavity is closed and fluid under pressure can flow through thevalve from the inlet port in such a manner that fluid pressure increasesat the pressure-responsive valving means; and second spool-actuatingmeans for moving the spool to its second position wherein fluid underpressure can flow through the valve without significant fluid pressureincrease in the first path, the second spool-actuating means beingdisposed in the second cavity, maintained in a first position while thepressure-responsive valving means is in its first position, and movableto a second position in response to a fluid pressure change in thesecond cavity resulting from movement of the pressure-responsive valvingmeans to its second position, the second actuating means beingpositioned so that it moves the spool to its second position uponmovement of the second actuating means to its second position.
 2. Avalve according to claim 1 wherein: the plurality of ports includes asecond drain port; and which further comprises fluid pressure reliefmeans connecting the second cavity to the second drain port forrelieving fluid pressure in the second cavity when thepressure-responsive valving means is in its first position.
 3. A valveaccording to claim 1 wherein: the plurality of ports further includes asecond drain port; the first path has a predetermined minimum diameterand communicates with a first portion of the second cavity, adjacent oneend thereof; the pressure-responsive valving means including a valveseat formed by a portion of the wall of the first path, a valve closuremember which, in the first position, cooperates with the seat to from afluidtight seal, and which, in the second position has moved away fromthe seat thereby allowing fluid pressure in excess of the predeterminedpressure to be transmitted to the second cavity, and adjustable biasingmeans cooperable with the closure member to yieldably bias the closuremember in the first position; the valve body further includes apassageway directly connecting one end of the first cavity to theopposite end of the second cavity and a second fluid-conducting pathconnecting the first portion of the second drain port, the second pathhaving a maximum diameter less than the minimum diameter of the firstpath; and the second spool-actuating means including piston meansslidably positioned in the second cavity in fluidtight engagement withthe walls thereof between the first portion and the opposite end,including a member operably connected to the piston means, slidablydisposed in the passageway, and adapted to cooperate with the spool tomove it to its second position when fluid pressure in excess of thepredetermined pressure is transmitted to the first portion of the secondcavity thereby moving the piston means toward the opposite end; andwhich further comprises yieldable bias means disposed in the secondcavity between the piston means and the opposite end for moving thepiston means away from the opposite end upon return of the closuremember to the first position.
 4. A valve according to claim 3 wherein:the spool includes an extension projecting through and outwardly fromthe valve body; and the first spool-actuating means includes a solenoidmounted coaxially with the extension and cooperable therewith to movethe spool to its first position upon application of electrical energy tothe solenoid, the solenoid being adapted for connection to a source ofelectrical energy.
 5. The valve according to claim 1 including: means tobias the pressure-responsive means to its first position, and adjustablemeans for selectively varying the biasing force on the predeterminedpressure can be adjusted.
 6. The valve according to claim 1 including:holding means to releasably locate the second spool actuating means inits first position until a substantial increase in pressure in thesecond cavity overcomes the holding means to move the further secondspool-actuating means to its second position.
 7. The valve according toclaim 6 wherein: the holding means comprises a yieldable detent actingon the second spool actuating means.
 8. A valve comprising: a valve bodyhaving a plurality of ports including an inlet port, a load port atleast one drain port communicating with a first interior cavity, thebody further having a second cavity, a first fluid-conducting pathconnecting the inlet port and the load port, and the inlet port and thesecond cavity, the load port and inlet port communicating with said onedrain port only through the first cavity, the inlet port beingconnectable to a hydraulic fluid supply, the load port being connectableto a hydraulic ram, and said one drain port being connectable to a fluidreservoir; a spool disposed in the first cavity and movable betweenfirst and second positions therein, said spool being constructed toblock communication between the inlet and load ports and said one drainport in the first position and to allow communication therebetween inthe second position; pressure-responsive valving means disposed in thefirst path between the inlet port and the second cavity and biased in afirst position until a predetermined fluid pressure within the firstpath is excEeded, the valving means being movable to a second positionby the fluid pressure when the predetermined pressure is exceededthereby causing a change in fluid pressure in the second cavity;connecting means operatively connecting the spool to a solenoid so thatactuation of the solenoid moves the spool to its first position whereinwhen the pressure-responsive valving means is in its first positionfluid under pressure can flow through the valve from the inlet port toonly the load port whereupon fluid pressure increases at thepressure-responsive valving mean; and hydraulically actuated means formoving the spool to its second position wherein fluid under pressure canflow from the inlet port and the load port to at least said one drainport with out significant fluid pressure increases in said first path,the hydraulically actuated means being disposed in the second cavity,maintained in a first position while the pressure-responsive valvingmeans is in its first position, and movable to a second position inresponse to a fluid pressure change in the second cavity resulting frommovement of the pressure-responsive valving means to its secondposition, the hydraulically actuated means being positioned so hat itmoves the spool to its second position upon movement of thehydraulically actuated means to its second position.
 9. The valveaccording to claim 8 including: holding means to releasably locate thehydraulically actuated means in its first position until a substantialincrease in pressure in the second cavity overcomes the holding means tomove the hydraulically actuated means to its second position.
 10. Thevalve according to claim 9 wherein: the holding means comprises ayieldable detent acting on the hydraulically actuated means.
 11. A valvecomprising: a valve body having a first interior cavity, a secondinterior cavity, a fluid-conducting path open to the first cavity andthe second cavity, and an inlet port and a load port communicating withthe path, a drain port communicating with the first cavity, a movablevalving member disposed in the first cavity movable in a first positionto block the flow of fluid from the path to the drain port and movableto a second position to permit the flow of fluid from the path to thedrain port, pressure-responsive valving means disposed in the pathbetween the inlet port and the second cavity, said pressure-responsivevalving means being maintained in a first position until a predeterminedfluid pressure within the path is exceeded, the valving means beingmovable to a second position by the fluid pressure when thepredetermined pressure is exceeded thereby causing an increase in fluidpressure in the second cavity, first actuating means for moving thevalving member to its first position, second actuating means for movingthe valving member to its second position wherein the fluid underpressure in the path can flow through the valve without significantfluid pressure increases in the path, said second actuating means beingdisposed in the second cavity and movable to a second position inresponse to a substantial increase in the fluid pressure in the secondcavity resulting from movement of the pressure-responsive valving meansto its second position.
 12. The valve according to claim 11 including:means to bias the pressure-responsive valving means to its firstposition, and adjustable means for selectively varying the biasing forceon the pressure-responsive valving means whereby the predeterminedpressure in the path can be adjusted. C
 13. The valve according to claim11 including: holding means to releasably locate the second actuatingmeans in its first position until a substantial increase in pressure inthe second cavity overcomes the holding means to move the actuatingmeans to its second position.
 14. The valve according to claim 13wherein: the holding means comprising a yieldable detent acting on theactuating means.
 15. The valve according to claim 11 wherein said firstactuating means includes: aN external control member for moving thevalving member to its first position.
 16. The valve of claim 11including: fluid pressure relief means connecting the second cavity to asecond drain port for relieving fluid pressure in the second cavity whenthe fluid pressure responsive valving means is in its first position.17. The valve according to claim 11 including: adjustable means forselectively varying the biasing force on the pressure responsive valvingmeans whereby the predetermined pressure in the path can be adjusted.